The present invention relates to sheet material feeders, for example hoppers for feeding sheet material such as signatures, individual sheets or inserts from a pile.
German Patent Application No. 197 38 920 for example discloses a feeder for taking a signature from a pile of signatures using a suction device, which passes the signature to a rotating drum. Grippers on further opening drums then open the signatures as the signatures are transported to a saddle-back conveyor.
U.S. Pat. No. 6,213,457 discloses an apparatus for feeding flat products from a pile using a sucker and conveying belts. The flat products are then passed to a feeder conveyor, either directly or via a gripper drum running at a stable surface speed ten percent greater than the speed of the flat products.